This node type would run an external command like (that is specified when you choose this node type):
powershell.exe MyCustomNode.ps1 ${NODE.CAPTION}
That would return a JSON output with the node details like, CPU, Memory, Volumes, Interfaces, and other details.
Simple example:
{
"CPU": 43.7,
"Memory": {
"Used": 4294967296,
"Total": 17179869184
},
"Volume": [
{
"Used": 17179869184,
"Name": "C:\\",
"Total": 107374182400
}
]
}